genode/os/src/server/nic_bridge/nic.cc

137 lines
3.5 KiB
C++

/*
* \brief NIC handler
* \author Stefan Kalkowski
* \date 2013-05-24
*/
/*
* Copyright (C) 2013 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU General Public License version 2.
*/
#include <base/env.h>
#include <net/ethernet.h>
#include <net/arp.h>
#include <net/ipv4.h>
#include <net/udp.h>
#include <net/dhcp.h>
#include "address_node.h"
#include "component.h"
#include "env.h"
#include "nic.h"
#include "vlan.h"
using namespace Net;
bool Net::Nic::handle_arp(Ethernet_frame *eth, Genode::size_t size) {
Arp_packet *arp = new (eth->data())
Arp_packet(size - sizeof(Ethernet_frame));
/* ignore broken packets */
if (!arp->ethernet_ipv4())
return true;
/* look whether the IP address is one of our client's */
Ipv4_address_node *node = Env::vlan()->ip_tree()->first();
if (node)
node = node->find_by_address(arp->dst_ip());
if (node) {
if (arp->opcode() == Arp_packet::REQUEST) {
/*
* The ARP packet gets re-written, we interchange source
* and destination MAC and IP addresses, and set the opcode
* to reply, and then push the packet back to the NIC driver.
*/
Ipv4_packet::Ipv4_address old_src_ip = arp->src_ip();
arp->opcode(Arp_packet::REPLY);
arp->dst_mac(arp->src_mac());
arp->src_mac(mac());
arp->src_ip(arp->dst_ip());
arp->dst_ip(old_src_ip);
eth->dst(arp->dst_mac());
/* set our MAC as sender */
eth->src(mac());
send(eth, size);
} else {
/* overwrite destination MAC */
arp->dst_mac(node->component()->mac_address().addr);
eth->dst(node->component()->mac_address().addr);
node->component()->send(eth, size);
}
return false;
}
return true;
}
bool Net::Nic::handle_ip(Ethernet_frame *eth, Genode::size_t size) {
Ipv4_packet *ip = new (eth->data())
Ipv4_packet(size - sizeof(Ethernet_frame));
/* is it an UDP packet ? */
if (ip->protocol() == Udp_packet::IP_ID)
{
Udp_packet *udp = new (ip->data())
Udp_packet(size - sizeof(Ipv4_packet));
/* is it a DHCP packet ? */
if (Dhcp_packet::is_dhcp(udp)) {
Dhcp_packet *dhcp = new (udp->data())
Dhcp_packet(size - sizeof(Ipv4_packet) - sizeof(Udp_packet));
/* check for DHCP ACKs containing new client ips */
if (dhcp->op() == Dhcp_packet::REPLY) {
Dhcp_packet::Option *ext = dhcp->option(Dhcp_packet::MSG_TYPE);
if (ext) {
/*
* extract the IP address and set it in the
* client's session-component
*/
Genode::uint8_t *msg_type = (Genode::uint8_t*) ext->value();
if (*msg_type == Dhcp_packet::DHCP_ACK) {
Mac_address_node *node =
Env::vlan()->mac_tree()->first();
if (node)
node = node->find_by_address(dhcp->client_mac());
if (node)
node->component()->set_ipv4_address(dhcp->yiaddr());
}
}
}
}
}
/* is it an unicast message to one of our clients ? */
if (eth->dst() == Net::Env::nic()->mac()) {
Ipv4_address_node *node = Env::vlan()->ip_tree()->first();
if (node) {
node = node->find_by_address(ip->dst());
if (node) {
/* overwrite destination MAC */
eth->dst(node->component()->mac_address().addr);
/* deliver the packet to the client */
node->component()->send(eth, size);
return false;
}
}
}
return true;
}
Net::Nic::Nic()
: _tx_block_alloc(Genode::env()->heap()),
_nic(&_tx_block_alloc, BUF_SIZE, BUF_SIZE)
{
_nic.rx_channel()->sigh_ready_to_ack(_sink_ack);
_nic.rx_channel()->sigh_packet_avail(_sink_submit);
_nic.tx_channel()->sigh_ack_avail(_source_ack);
_nic.tx_channel()->sigh_ready_to_submit(_source_submit);
}